There has been some confusion since about JO about blender maps and detail maps. Hopefully this thread will end that confusion
once and for all.

What is a Blender/ Blend map?

A blender map is an RGBA .TGA file that is used in conjunction with the detail maps in order to apply textures to specific areas
in the terrains.

What is a Detail map?

A detail map is an RGBA or RGB .TGA file that has a texture(s) that is applied to the terrain in one of two ways:

Multiplied to color map - one or more RGBA channels of the detail map is multiplied to the terrain's color map.

Overlaps the color map - the RGB detail map is directly applied to the terrain and overrides any tinting done by the color map. The
Alpha channel is ignored

Type 2 detail maps are used for close-up terrain when the "Terrain" option (in game options) is set to High.

Type 1 detail maps are used for terrain that is further away from the player. It is also used for close-up terrain when the "Terrain" option (in
game options) is set to Normal or Low.

How does the game use Blender and Detail Maps?

When the game loads up the terrain, all 4 detail maps are automatically applied to the terrain, and then uses the Blender map to
controls the transparency of those textures at specific spots.

Single-Channel Blender Map Example

This blender map is an example of a single-channel blender map. Areas that are pure Red have the detail map fully visible on the terrain, while areas
that are pure black have the detail map transparent. Shades of red in-between have varying levels of opacity.

Dual-Channel Blender Map Example

This blender map is an example of a dual-channel blender map. The same mechanics explained before is still used here, but each color represents a
different detail map: such as red being dirt areas while green being grassy areas.

Detail Map Hierarchy

The maps are layered top-down in this order:

Red

Green

Blue

Alpha

Layers at the top (smaller number) are rendered over the lower layers. So if you have an Area that has a lot of Red on it, then the Green, Blue, and
Alpha layers will be rendered, but not seen by the player.

Differences between Type 1 Detail maps and Type 2 Detail Maps

Type 1 Detail maps have their channels directly correspond with the blender map channels. The Red channel will be applied to red
blend areas, the Green channel with the green blend areas, etc.

Type 2 Detail maps, since they're not split up into channels, must be defined in the .TRN for each blend channel: